Winding device for a blind without pull cords

ABSTRACT

A winding device for a blind without pull cords is provided with a reel pivotal base and a cord-guiding base abutting against each other in the upper rail of a blind. A winding reel is axially assembled on the reel pivotal base, having its outer circumference formed with an oblique conical surface gradually shrinking from its first end to its second end to enable a linking cord to move forward automatically when the linking cord is wound on the winding reel. The cord-guiding base is provided with at least one push block at a location where the winding reel is pivotally rotated for guiding the linking cord to be wound side by side closely on the winding reel, preventing the linking cord from overlapping or wound irregularly after the linking cord is wound on the winding reel, enabling a blind to be collapsed or stretched smoothly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a winding device for a blind without pull cords, particularly to one able to wind and release the linking cords of a blind comparatively smoothly.

2. Description of the Prior Art

A conventional blind without pull cords has its upper rail installed with an elastic force mechanism and a rotating shaft actuated to rotate by the elastic force mechanism and connected in series with the two winding reels of two winding devices at the opposite sides of the elastic force mechanism. When a blind is pushed upward, the elastic force mechanism will indirectly actuate the two winding reels to rotate through the rotating shaft and the linking cords threaded the slats of a blind and connected with a lower rail will be wound on the two winding reels, and when the blind is drawn downward, the linking cords wound on the winding reels will be drawn and released. Each winding device is further provided with a reel pivotal base in the upper rail for the winding reel to be axially assembled thereon.

However, when the conventional winding devices are operated to wind the linking cords of a blind, it is usually found that some parts of the linking cords cannot be wound side by side closely on the winding reels while other parts of the linking cords are likely to overlap one another after wound on the winding reels, impossible to wind and release the linking cords properly and, consequently, failing to collapse and stretch a blind smoothly. In addition, if the two opposite winding reels carry out winding of the linking cords at the opposite sides of a blind at different speeds, there will produce different levels between the opposite sides of the blind, thus affecting integral beauty of the blind.

SUMMARY OF THE INVENTION

The objective of the invention is to offer a winding device for a blind without pull cords, provided with a reel pivotal base and a cord-guiding base abutting against each other in the upper rail of a blind. A winding reel is pivotally and axially assembled on the reel pivotal base and has its outer circumference formed with an oblique conical surface gradually shrinking from its first end to its second end to enable linking cords of a blind to automatically move toward the second end of the winding real when the linking cords are wound on the winding reels. The cord-guiding base is provided with at least one push block at a location where the winding reel is pivotally rotated, for guiding the linking cords to be wound side by side closely on the winding reel, preventing the linking cords from overlapping or wound irregularly after being wound on the winding reel and enabling the blind to be collapsed or stretched smoothly.

BRIEF DESCRIPTION OF DRAWINGS

This invention will be better understood by referring to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a first preferred embodiment of a winding device assembled with the upper rail of a blind without pull cords in the present invention:

FIG. 2 is a perspective view of the first preferred embodiment of the winding device in the present invention:

FIG. 3 is an exploded perspective view of the first preferred embodiment of the winding device in the present invention:

FIG. 4 is a partial upper cross-sectional view of the first preferred embodiment of the winding device starting to wind the linking cord of a blind on winding reel in the present invention:

FIG. 5 is a partial upper cross-sectional view of the first preferred embodiment of the winding device finishing winding the linking cord of the blind on the winding reel in the present invention: and

FIG. 6 is a perspective view of a second preferred embodiment of the reel pivotal base of a winding device to be assembled with the upper rail of a blind in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A first preferred embodiment of a winding device to be installed in the upper rail of a blind without pull cords in the present invention, as shown in FIGS. 1, 2 and 3, includes a reel pivotal base 10, a winding reel 20, a cord-guiding base 30 and a cover 40 as main components combined together.

The reel pivotal base 10 is formed with a recessed groove 11 with an opening facing upward. The recessed groove 11 has the central upper edge of its two lateral walls respectively cut with an arc-shaped notch 12 larger than a semicircle, and also has its two lateral walls and the central portion of its bottom respectively bored with a cord hole 13 for a linking cord 60 to pass therethrough. Further, the reel pivotal base 10 is provided with a positioning stud 14 at the central portion of its bottom to be inserted and positioned in an insert hole 511 in the groove bottom 51 of the upper rail 50, with the threading hole 13 located in the center of the positioning stud 14. Furthermore, the reel pivotal base 10 has its front and rear outer wall respectively fixed thereon with an elastic clasping member 15 protruding outward to be elastically clasped in two slot ways 52 formed at top of the opposite sides of the upper rail 50.

The winding reel 20 is a hollow shaft and has the central portion of its opposite ends respectively formed with a polygonal shaft hole 21 for receiving there in a rotating shaft 71 that is actuated to rotate by the elastic torsion produced by an elastic force mechanism 70. The winding reel 20 is formed with a first end 22 and a second end 23. The first end 22 of the winding reel 20 has its outer circumferential surface provided with two annular flanges 221 separated from each other at a proper distance to be engaged with the inner wall of the two arc-shaped notches 12 of the reel pivotal base 10, letting the winding reel 20 axially restricted in position and able to rotate freely. The second end 23 of the winding reel 20 has its outer circumferential surface provided with an annular flange 231 and bored with an insert hole 232 near the inner side of the annular flange 231, with the first end 61 of a linking cord 60 inserted through the insert hole 232 and tied into a knot to be fixed therein. The winding reel 20 further has its outer circumferential wall formed with an oblique conical surface 24 gradually shrinking from the first end 22 to the second end 23.

The cord-guiding base 30 has its underside provided with two protruding arc-shaped members 31, as shown in FIG. 4, to be inserted and positioned in an engage hole 512 adjacent to the inner side of the insert hole 511 in the groove bottom 51 of the upper rail 50. Two protruding elastic hooking members 32 are disposed between the two arc-shaped members 31 to be elastically hooked on the underside wall of the engage hole 512 of the upper rail 50, letting the cord-guiding base 30 abut against the inner side of the reel pivotal base 10. Further, the cord-guiding base 30 has its central portion formed with a vertical wall 33 having its central upper edge cut with an arc-shaped notch 331 larger than a semicircle for receiving a relative portion of the winding reel 20, with a proper gap formed between the winding reel 20 and the arc-shaped notch 331. The vertical wall 33 of the cord-guiding base 30 has one side below the arc-shaped notch 331 bored with a cord hole 332 aligned to the cord hole 13 in one lateral wall of the reel pivotal base 10. The second end 62 of the linking cord 60 is inserted through the cord hole 332 of the cord-guiding base 30 and through the cord holes 13 in one lateral wall and in the bottom of the reel pivotal base 10 and then threaded through the slats of a blind 80 to be connected with a lower rail 90.

Further, the vertical wall 33 has its opposite lateral walls respectively and symmetrically formed with a first push block 34 and a second push block 35 at the lateral edge of the arc-shaped notch 331 and along the winding course of a linking cord 60 after the linking cord 60 is threaded through the cord hole 332. One side of the first and the second push block 34, 35 are flush with the inner edge of the arc-shaped notch 331. The first push block 34 is formed with a bulged support surface 341 and the second push block 35 is formed with a support surface 351 gradually slanting upward along the winding course of the linking cord 60. In addition, the lowermost portion of the support surface 351 of the second push block 35 is about positioned at the level of the support surface 341 of the first push block 34, and the length of the second push block 35 is about one fourth of an imaginary circle of the arc-shaped notch 331.

The cover 40 is covered on the winding reel 20 and has one end engaged with the reel pivotal base 10, with a space formed between the inner wall of the cover 40 and the outer wall surface of the winding reel 20 for receiving the linking cord 60 wound on the winding reel 20.

A second preferred embodiment of a winding device for a blind without pull cords in the present invention, as shown in FIG. 6, has almost the same structure as that described in the first preferred embodiment, except that two hooking plates 16 instead of the two elastic clasping members 15 are respectively fixed at the front and the rear outer walls of the reel pivotal base 10 so that the reel pivotal base 10 can be firmly combined with the upper rail 50 by means of the two hooking plates 16 respectively hooked in the opposite slot ways 52 of the upper rail 50.

Referring to FIG. 1, when a user applies a force to lift a blind 80 stretched downward, the elastic force mechanism 70 will indirectly actuate the winding reels 20 to rotate through the rotating shafts 71 and force the linking cords 60 to be orderly wound on the winding reel 20. In a winding process, the linking cord 60 continuously drawn out of the cord hole 332 of the cord-guiding base 30 will first touch the bulged support surface 341 of the first push block 34, which is provided along a winding course, and be pushed to move toward the second end 23 of the winding reel 20, as shown in FIG. 4. Subsequently, the linking cord 60 will touch the slanting-up support surface 351 of the second push block 35, which is positioned higher than the support surface 341 of the first push block 34 and provided along the winding course, and be guided to move toward the second end 23 of the winding reel 20. With the help of the outer circumferential oblique conical surface 24 of the winding reel 20, which is gradually shrunk from the first end 22 to the second end 23, the linking cord 60 can be orderly wound toward the second end 23 of the winding reel 20, letting each circle of the linking cord 60 wound on the winding reel 20 and lean against one another closely, as shown in FIG. 5, to prevent the linking cords 60 on the winding reel 20 from overlapping or separating. By so designing, the linking cords 60 of a blind 80 can surely be wound or unwound smoothly and therefore, the blind 80 can also be collapsed or stretched smoothly, avoiding producing different levels at the opposite sides of a blind and able to keep integral beauty of the blind.

While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention. 

1. A winding device for a blind without pull cords comprising: A reel pivotal base installed at a preset portion of the upper rail of a blind; A winding reel formed with a first end and a second end, said first end of said winding reel pivotally and axially assembled on said reel pivotal base, a linking cord having its first end fixed in said second end of said winding reel, said winding reel having its outer circumference formed with an oblique conical surface gradually shrinking from said first end to said second end; and A cord-guiding base installed in said upper rail and abutting against said reel pivotal base, said cord-guiding base formed with a vertical wall, said vertical wall having its central upper edge cut with an arc-shaped notch, said arc-shaped notch receiving a relative portion of said winding reel, a gap formed between said winding reel and said arc-shaped notch.
 2. The winding device for a blind without pull cords as claimed in claim 1, wherein said reel pivotal base has its, bottom and one lateral wall respectively bored with a cord hole for a linking cord to pass therethrough.
 3. The winding device for a blind without pull cords as claimed in claim 1, wherein said vertical wall of said cord-guiding base is bored with a cord hole at one side near said arc-shaped notch for the second end of said linking cord to pass therethrough, said second end of said linking cord then threaded through said cord hole in the lateral wall and in the bottom of said reel pivotal base.
 4. The winding device for a blind without pull cords as claimed in claim 1, wherein said arc-shaped notch of said vertical wall of said cord-guiding base has a preset portion of its lateral edge provided with at least one protruding push block facing said second end of said winding reel, said push block guiding and pushing said linking cord to move toward said second end of said winding reel after said linking cord is threaded out of said cord hole of said vertical wall of said cord-guiding base, enabling said linking cord to be wound side by side orderly and closely on said winding reel.
 5. The winding device for a blind without pull cords as claimed in claim 4, wherein said push block of said cord-guiding base is formed with a support surface gradually slanting-up along the winding course of said linking cord.
 6. The winding device for a blind without pull cords as claimed in claim 4, wherein said arc-shaped notch of said cord-guiding base has its lateral edges orderly provided with a first push block and a second push block along the winding course of said linking cord.
 7. The winding device for a blind without pull cords as claimed in claim 4, wherein one side of said push block is flush with the inner edge of said arc-shaped notch.
 8. The winding device for a blind without pull cords as claimed in claim 4, wherein said vertical wall of said cord-guiding base has its opposite lateral walls respectively and symmetrically provided with a push block.
 9. The winding device for a blind without pull cords as claimed in claim 6, wherein said second push block of said cord-guiding base is formed with a support surface gradually slanting-up along the winding course of said linking cord, the lowermost portion of said support surface of said second push block about positioned at a same level of the support surface of said first push block.
 10. The winding device for a blind without pull cords as claimed in claim 6, wherein said second push block is arc-shaped and the length of said second push block is about one fourth of an imaginary circle of said arc-shaped notch of said cord-guiding base.
 11. The winding device for a blind without pull cords as claimed in claim 1, wherein a cover is covered on said winding reel and has one end engaged with said reel pivotal base, with a space formed between the inner wall of said cover and the outer wall of said winding reel for receiving said linking cord wound on said winding reel. 